Supramolecular Strategies for Controlling Reactivity within Confined Nanospaces

Abstract

Nanospaces are ubiquitous in the realm of biological systems and are of significant interest among supramolecular chemists. Understanding chemical behavior within nanospaces offers new perspectives on biological phenomena in nature and opens the way to highly unusual and selective forms of catalysis. Supramolecular chemistry exploits weak, yet effective, intermolecular interactions such as hydrogen bonding, metal‐ligand coordination, and the hydrophobic effect to assemble nano‐sized molecular architectures, providing reactions with remarkable rate acceleration, substrate specificity, and product selectivity. In this minireview, the focus is on the strategies that supramolecular chemists use to emulate the efficiency of biological processes, and elucidating how chemical reactivity is efficiently controlled within well‐defined nanospaces. Approaches such as orientation and proximity of substrate, transition‐state stabilization, and active‐site incorporation will be discussed.

Emergent behavior in nanoconfined molecular containers

“…In addition to the stabilization of transition states, the cavities of the containers are able to accelerate reaction rates as a result of substrate preorganization, desolvation, and local concentration enhancement. Hu 227 has summarized the science of supramolecular catalysis in confined nanospaces. Catalytic reactions within the pockets of coordination containers have been reviewed by Zhou.…”

Whither Second-Sphere Coordination?

“…Significant advances have been made in creating these artificial enzymes, as summarized [211][212][213][214][215][216][217][218][219][220][221] in several excellent reviews. It turns out that second-sphere coordination has been exploited widely as an emerging strategy for designing artificial enzymes by encapsulating catalysts inside molecular containers, leading to high efficiencies and excellent regio-and stereoselectivities being achieved at the catalytic centers.…”

A Water‐ and Base‐Stable Iminopyridine‐Based Cage That Can Bind Larger Organic Anions

“…Potential applications range from chemical transport or separation [1–11] and molecular sensing [12–17] to the stabilization of reactive guests [18–27] . Moreover, catalysis has also been a major focus in self‐assembled molecular capsules and cages [28–49] . Out of the reactions catalysed most examples feature cationic intermediates and transition states.…”